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Robotics and systems technology for advanced endoscopic procedures:experiences in general surgeryqMarc O.Schurr*,Alberto Arezzo,Gerhard F.BuessSection for Minimally Invasive Surgery,Eberhard-Karls University,Tuebingen,GermanyAbstractThe advent of endoscopic techniques changed surgery in many regards.This paper intends to describe an overview about technologies tofacilitate endoscopic surgery.The systems described have been developed for the use in general surgery,but an easy application also in the®eld of cardiac surgery seems realistic.The introduction of system technology and robotic technology enables today to design a highlyergonomic solo-surgery platform.To relief the surgeon from fatigue we developed a new chair dedicated to the functional needs ofendoscopic surgery.The foot pedals for high frequency,suction and irrigation are integrated into the basis of the chair.The chair is drivenby electric motors controlled with an additional foot pedal joystick to achieve the desired position in the OR.A major enhancement forendoscopic technology is the introduction of robotic technology to design assisting devices for solo-surgery and manipulators for micro-surgical instrumentation.A further step in the employment of robotic technology is the design of`master-slave manipulators'to provide thesurgeon with additional degrees of freedom of instrumentation.In 1996 a ®rst prototype of an endoscopic manipulator system,namedARTEMIS,could be used in experimental applications.The systemconsists of a user station (master) and an instrument station (slave).Thesurgeon sits at a console which integrates endoscopic monitors,communication facilities and two master devices to control the two slavearms which are mounted to the operating table.Clinical use of the system,however,will require further development in the area of slavemechanics and the control system.Finally the implementation of telecommunication technology in combination with robotic instrumentswill open new frontiers,such as teleconsulting,teleassistance and telemanipulation.q1999 Elsevier Science B.V.All rights reserved.Keywords:Endoscopic surgery;Robotics;Solo-surgery;Systems;Telemedicine1.Introduction1.1.The role of technology in minimally invasive surgeryThe advent of endoscopic techniques changed surgery inmany regards.Besides the adaptation to newkinds of instru-mentation and operative maneuvers,the surgeon had to copewith a full range of new devices resulting in a signi®cantchange of his work-place environment.Starting out fromtheearly 1990s,the design of dedicated surgical work-placesystems for minimally invasive surgery still is a majortopic for research and industry.With the increasing complexity of endoscopic surgery inthe various clinical specialties,such as general,cardiac orgynaecologic surgery,came the demand for improvedinstrumentation.This paper intends to describe an overviewabout technologies to facilitate endoscopic surgery.Thesystems described have been developed for the use ingeneral surgery.However,due to the technical similaritiesin all surgical disciplines using minimally invasive techni-ques,devices and experiences collected with themshould betransferable to cardiac surgery as well.Besides improvements in the ®eld of endoscopic visionsystems [1±3] leading research groups world wide focustheir scienti®c interest especially on the increase of instru-ment functionality.Robotics was soon recognized as a majorpacemaker in the drive towards the technological future ofendoscopic surgery.The initial steps in the use of robotics forincreasing instrument functions were in the ®eld of endo-scope guidance,where robotic instrument holders wereemployed to direct the endoscope during surgery [3±5].Robotic endoscope manipulators proved to be safe and ef®-cient invarious ®elds of use andare nowacceptedas assistingdevices among endoscopic surgeons [6].The ®eld of robotics for enhancing surgical instrumenta-tion did not emerge as quickly as the former due to its highertechnical complexity and safety questions linked to the useof robotic devices for surgical tissue manipulation.It is,European Journal of Cardio-thoracic Surgery 16 (Suppl.2) (1999) S97±S1051010-7940/99/$ - see front matter q 1999 Elsevier Science B.V.All rights reserved.PII:S1010-7940(99)00281-Xwww.elsevier.com/locate/ejctsqPresented at the International Symposium`Present State of MinimallyInvasive Cardiac Surgery ± Meet the Experts',Dresden,Germany,Decem-ber 3±5,1998.* Corresponding author.Section for Minimally Invasive Surgery,Eber-hard-Karls University,Waldhoernlestrasse 22,D-72072 Tuebingen,Germany.Fax:149-7071-295-569.however,of key scienti®c and clinical interest for endo-scopic suturing.Besides robotics,systems technology will have signi®-cant impact on work processes in the OR.The integrationof the different devices used for endoscopic operations intosystems structures,which are easy to control and to main-tain,is an important prerequisite for optimizing processesand resource allocation in surgery.Finally,telecommunication technologies applied tosurgery will help to leverage surgical expertise amongcenters,facilitate information transfer and accelerate thediffusion of surgical techniques among leading centers.2.Enabling technologies in the endoscopic ORNewtechnologies are of great help in the design of instru-ments for endoscopic OR.The introduction of system tech-nology and robotic technology enables today to design ahighly ergonomic solo-surgery platform.With the additionof telecommunication technology assistance,consulting andmanipulation from a remote distance become possible.3.Systems technology to create an ergonomic work placein the ORMinimally invasive interventions require a multitude oftechnical devices,such as cameras,light-sources,high-frequency and isuf¯ation.The devices used today oftenrepresent stand-alone units.They need to be put into theOR and set-up right before each speci®c surgery.Fromeach of the single devices,cables,hoses and other supplieslead into the operative ®eld.They have to be connected onboth sides.This does not only cause long set-up times in theOR but is also a source for infringement of the sterility ofthe operating ®eld.The major drawback of the standardsolution lies in the lack of direct control of the devicesand the confusing display of parameters and technical statusof the single devices.The ®rst approach to solve these problems has been madewith the Dornier OREST system in the early 1990s [7].OREST (Fig.1) integrates all devices into a mobile cabinet.The single devices are connected to a central computer andcan be controlled remotely by the surgeon via a multifunc-tional monitor and input panel.This panel also informsabout all function parameters on a graphical display.Allsupplies are guided into the sterile ®eld through an articu-lated arm.Up to four multi-plugs are used to connect alllines at a central terminal within the sterile area.Based on the same principle,other system solutions arenowavailable on the market fromdifferent companies,suchas the ENDOSURG system (Olympus,Tokyo) and theHERMES system (Computer Motion,Goleta).The posture of the surgeon during endoscopic interven-tions differs signi®cantly fromregular open procedures.Thelong shafts of the instruments and the ®xation of the line ofsight to the video monitor decrease the freedomof motion ofthe surgeon.Compared to open surgery the endoscopicsurgeon remains ®xed to his position during the operationwith little opportunity to move his body and change hisposture.This ®xation in a relatively unergonomic positioncan cause fatigue especially during longer interventions.Wedeveloped a newsurgeon's chair dedicated to the functionalneeds of endoscopic surgery (Fig.2).The foot pedals forhigh frequency,suction and irrigation are integrated into thebasis of the chair.This provides for an intuitive alignment ofthe foot pedals to the feet of the surgeon.The chair is drivenby electric motors controlled with an additional foot pedaljoystick.The seat offers a special ergonomic shape,whichallows both comfortable sitting in a semi-standing positionand inclination towards the OR table without slipping off.The chair is applicable for various kinds of endoscopicsurgery.The device can be used in conventional teamsurgery with one surgeon and one or two assistants.However the combination with endoscopic solo-surgerytechniques seems particularly attractive.4.Robotics and solo-surgeryCurrently robotics technology has two main applicationsin minimally invasive surgery:assisting devices for solo-M.O.Schurr et al./European Journal of Cardio-thoracic Surgery 16 (Suppl.2) (1999) S97±S105S98Fig.1.OREST II system (Dornier,Germany).surgery and robotic manipulators for enhanced microsurgi-cal instrumentation.4.1.Solo-surgerySince minimally invasive surgery appeared,the vision ofthe operating surgeon has depended by an assistant surgeonresponsible for positioning the endoscope.This taskrequires to keep the surgical point of interest in the centerof the video frame,providing an appropriate magni®cationand maintaining a horizontal image.The use of positioning devices returns direct control ofthe whole procedure to the operating surgeon.Thisincreases precision of action and reduces costs.In thepast,mechanical arms and pneumatically assisted devicesderived fromopen surgery were used.The lack in ergonomyresulted in a scarce diffusion of use of these systems.Theintroduction of manipulator technology,has opened newfrontiers in the development of MIS systems.The ®rst endoscopic positioning system appeared on themarket was the AESOP arm (Computer Motion,Goleta) in1995 [5].It moves the endoscope around a pivoting point.Up to now more than 50 000 procedures have beenperformed in the United States.The experience in clinicalsettings was used to upgrade the systemsubstantially,®rst inthe version named 2000,with the implementation of a voicecontrol system,then,in the least version,named 3000,witha second joint that allows to reduce space requirements.Another system also available on the market is theENDOASSIST (Armstrong Helthcare,UK).The systemmoves the endoscope around an invariant point of constraintmotion,that has to be pre-adjusted.Apointer is placed in thefront of a helmet held by the surgeon and a visual detectorover the monitor.This way each movement of the head isdetected and the information transferred to the computerthat moves the optic in a correspondent way.The systemis ®xed on a trolley and its architecture design has minimumspace requirements.In cooperation with the Research Center,Karlsruhe wedesigned a passive positioning arm,named TISKAEndoarm[8] (Fig.3) and a remote controlled optic position-ing arm,named FIPS Endoarm,for endoscopic surgery.Both prototypes are based on an architecture that ®xes aninvariant point of constraint motion.TISKAEndoarmmain-tains a stable position by means of an electromagnetic fric-tion that is released by footpedal.The operation of thesystem is possible by using only one hand.The system ishighly appreciated when used as instrument retractor.FIPSEndoarm (Fig.4) is an optic positioning system driven byvoice control or by a ®nger ring joystick which is clipped onthe handle of the operating instrument.As the tip of thesecond ®nger is introduced in the controller,its movementscorrespond to the movement of the optic.In different trials conducted on phantoms at our institu-tion more than 300 procedures were performed.Endoscopicsolo-surgery proved feasibility and safety.A number ofsurgeons involved in the study declared positive judgmentin terms of comfort for each of the different interfacestested.All endoscope positioning systems combined withan instrument retractor allowed a precise and comfortablecontrol of the optic.With all combination of systems opera-tive time requirement was shorter than human assistance.Nevertheless,the shorter operative time was registeredwhen the endoscope was driven by a passive systemTISKA Endoarm.This demonstrates the important role ofthe man-machine interface,that in none of the solutionstested showed an intuitiveness and reliability competitivewith hand positioning.The trials conducted allowed us also to focus on thecrucial aspect concerning the position of the devices aroundthe operating table.We were able to de®ne criteria,how toperformendoscopic solo-surgery ergonomically (Fig.5).Tolimit possible interferences between surgeon and the assistdevices,these have to be placed all opposite to the surgeon.The surgeon works in a comfortable position having accessto the surgical ®eld by means of a conventional straightinstrument and a curved instrument as designed byCuschieri.4.2.Robotic microsurgical manipulatorsIn endoscopic operations the mobility of the instrument issigni®cantly decreased due to the invariant point of insertionthrough the patient's abdominal or thoracic wall [9±11].Only four of the seven`natural'degrees of freedom(DOF) of the human arm remain [11].This reduction ofinstrument mobility is not an issue in simple manipulationsdominating laparoscopic cholecystectomy or herniasurgery,but it can lead to signi®cant handling restrictionsM.O.Schurr et al./European Journal of Cardio-thoracic Surgery 16 (Suppl.2) (1999) S97±S105 S99Fig.2.Ergonomic chair for endoscopic surgery.for the surgeon in interventions where complex dissection ortissue connection techniques are required.Complex,user driven robotic systems,called`master-slave manipulators'have been developed to provide thesurgeon with additional DOF of instrumentation.Themaster-slave mode of operation is a control principle inwhich all movements done with a master input device aretransformed in real-time to the slave output device [12,13].The entire manipulator systemcan be guided by the user,nopre-programmed`robotic'motion is happening.Our own development in the area of surgical roboticsstarted in 1991,together with the Karlsruhe ResearchCenter,Karlsruhe,Germany.In 1996 a ®rst prototype ofan endoscopic manipulator system could be used in experi-mental applications.The ARTEMIS (Advanced Robotic TElemanipulator forMinimally Invasive Surgery) manipulator system has twobasic components,the user station (master) and the instru-ment station (slave).The surgeon sits at a console whichintegrates endoscopic monitors,communication facilitiesand two master devices to control the two slave armswhich are mounted to the operating table.The slave arm is an external kinematic unit to guide asteerable instrument around the invariant point of insertioninto the body of the patient.The arm has two segments andfour joints,which are driven by integrated electromotors.The steerable instruments have a bending section,whichallows to incline the tip around 908.The functional unit of both,steerable instrument andguiding arm,restores full spatial mobility of the instrumenttip with 6 DOF of motion.Two slave units (Fig.6) can beattached to the operating table.The surgeon's work place comprises an endoscopic 3Dmonitor for visualization of the operative ®eld,as well astwo additional monitors for display of a graphical model ofthe slave arms and various system data.After appropriate system function and safety could beproven in phantom models,animal experiments wereperformed in domestic pigs (female,weight approx.50kg) under general anesthesia.ARTEMIS arm was employed for mobilization of thesigmoid colon and ligation of sigmoid vessels for laparo-scopic sigmoidectomy.The master arm was positionedaside the operating table,the surgeon was in a sitting posi-tion (Fig.7).After dissection of the sigmoid colon andfenestration of the mesentery the blood vessels wereencircled and ligated with the ¯exible section of the steer-able instrument.Several ligatures were placed at differentheights of the colon.The maneuver was easy to perform.Itwas found,however,that geometric changes in the ¯exibletip section are required to improve practicality of the device.Further steps of surgical evaluation are planned after modi-®cation of the prototype.5.Telecommunication technologyTelematics applications are of interest in various ®elds ofM.O.Schurr et al./European Journal of Cardio-thoracic Surgery 16 (Suppl.2) (1999) S97±S105S100Fig.3.TISKA endoarm.medicine.In therapeutic areas,such as all surgical disci-plines,telemedicine has future relevance,but is not as wide-spread as on the diagnostic side.Three levels of telematics applications in surgery can bedistinguished:teleconsulting,teleassistance and telemani-pulation.Whereas the ®rst is based on intraoperative video-conferencing and bilateral audio-visual communications,the two other levels include remote guidance of an endo-scope or even surgical instruments by a remote expert.We estimate,that teleconsulting techniques will enter theclinical routine of centers relatively soon,whereas teleas-sistance and telemanipualtion technologies will not result inclinical breakthroughs within the next few years.Clinical and ambulatory patient care are processes with agreat deal of information to be handled.Therefore advancedinformation management and telecommunications servicesare of particular interest for the various medical disciplines[13,14].The technological basis of teleconsulting applicationsusually is ISDN teleconferencing using two ISDN B-chan-nels totaling to a transmission rate of 128 kbit/s (Europe) or112 kbit/s (USA).These transmission rates are not suitablefor real-time applications.Image resolution and image ratesper second are visibly reduced compared to PAL or NTSCTV standards.5.1.Surgical teleconsultingIn the clinical ®eld we were able to study teleconsultingapplications with several external partners in a six B-chan-nel setting providing a bandwidth of 384 kbit/s.A four site teleconsulting trial was performed includingTuebingen University Hospital,the Karlsruhe ResearchCenter and the Institute of Research on Digestive TractCancers (IRCAD),Strasbourg,and a moderator located atKiel.The clinical case was an endoscopic removal of arectal tumour through the transanal TEM approach.The scienti®c question to answer through the experimentswas whether the given bandwidth is suf®cient for appropri-ate image quality.In different phases of the intervention(tumour dissection,closure of the rectal wall defect) exter-nal`teleconsultants'from both the technical side (Karls-ruhe) and the clinical side (Strasbourg) were confrontedwith questions on the case by the operating surgeon.The image resolution was judged by all teleconsultants tobe suf®cient but at the lower end of acceptability for on-lineinvestigations.Usually video transmission is perceived real-time with a bandwidth not less than 2 mbit/s.This requiresATMconnections which are costly and hardly available formost hospitals.The overall judgment of the participants in the experi-ments was that six B-channel teleconferencing techniquesare feasible for intraoperative surgical consulting,providedthat the operative ®eld,the instruments or the endoscopeitself are not moving signi®cantly.Considering the simple and standardized technologicalbasis of ISDN telephone systems surgical intraoperativeM.O.Schurr et al./European Journal of Cardio-thoracic Surgery 16 (Suppl.2) (1999) S97±S105 S101Fig.4.FIPS endoscope guiding system.Fig.5.Placement of positioning systems for endoscopic solo-surgery.teleconsulting could soon become clinically feasible forsurgical centers.5.2.Surgical teleassistanceDuring intraoperative teleassistance the remote consul-tant has access to move the endoscope to adjust the endo-scopic image according to his own preferences.Thisrequires the combination of telecommunications withrobotics technology.Several trials have been made by ourgroup as well as by several other researchers worldwide.Inall applications a robotic endoscope guidance system isconnected to any kinds of communication lines or networks.Control data are transmitted along appropriate lines (ISDNor B-ISDN) together with video and voice data.Usuallyrobotic control data require a lower bandwidth comparedto mass data such as video or audio so that their transmissiondoes not add too much complexity to the set-up in terms oftelecom capacities.Our current research is focused on using bundled ISDNlines for remote guidance of the FIPS endoscope guidingsystem.5.3.Surgical tele-manipulationThe ®eld of surgical tele-manipulation is subject to inten-sive research worldwide.Surgical tele-manipulation is characterized by perform-ing an operation or phases of an operation without beingphysically present at the operating table.The ®eld of surgi-cal tele-manipulation is always linked to both advancedcommunication technologies and robotics.A number of research groups worldwide have assessedthe potential of tele-manipulation systems in experimentalsettings for several years.Especially the medical engineer-ing group at SRI,Menlo Park,put particular emphasis onthis topic [15].Our own involvement in this ®eld started in 1994 with ourinitial evaluations of the DISTEL manipulator system [16].The Karlsruhe DISTEL manipulator system was modi®edfor this purpose.The original system is a one arm masterslave manipulator with six motion axes.Its purpose of use isremote handling of dangerous substances in the technical®eld.For surgical application a conventional rigid instru-ment was attached to the manipulator arm.The distancebetween both sides of the system was 1.3 km.Communica-tion and data transfer between both sites are possible along abundle of 12 ®beroptic cables.With the appropriate trans-mission bandwidth the distance between the two sites is notrelevant.Through broad band ATM connections therewould be no major functional difference between the present1.3 kmor several thousands of kilometers.With this systemseveral tests were carried out for the assessment of telesur-gical working conditions for the user.A standardized series of repetitive task-board experi-ments was carried out by two groups,surgeons and engi-neers [16].It was found that persons with experience inendoscopy adapted much faster to the remote handlingsituation than those without appropriate experience.M.O.Schurr et al./European Journal of Cardio-thoracic Surgery 16 (Suppl.2) (1999) S97±S105S102Fig.6.The ARTEMIS manipulator system.The steerable instrument is introduced into a phantom.Telecommunications technology will have great impacton future scienti®c and clinical work in most medical areas[13,14,17].Surgery,being a therapeutic specialty,has notbeen very receptive for telematics applications so far.M.O.Schurr et al./European Journal of Cardio-thoracic Surgery 16 (Suppl.2) (1999) S97±S105 S103Fig.8.Newendoscope (MGB,Berlin) with additional illumination source for enriching image contrast.In addition,the scope has nozzles for rinsing the frontlens.Fig.7.The manipulator applied in an animal experiment (one arm version).Teleconsulting techniques based on intraoperative tele-conferencing are becoming clinically feasible and arealready used in specialized centers.Teleassistance techni-ques with remote control of the endoscope is getting tech-nically feasible for routine use,too,after it has been widelydemonstrated by different research groups.From our pointof view these applications will ®nd entrance into clinicalsurgery within the next few years.However,If the complextechnologies merging robotics and telematics for telemani-pulation will be of practical clinical value in the near andmid-term future,is still doubtful.6.DiscussionThe restoration of functional qualities,which are avail-able in open surgery,is an important demand for furtheringendoscopic surgery.This is of particular interest for therestoration of basic functions of man-environment interac-tions,such as spatial vision [1,2],tactile sense and instru-ment mobility in the operative ®eld [18].Developments ofthe last few years in the ®eld of endoscopic vision systems[3] have led to more natural endoscopic visualization interms of improved image resolution,illumination,andclear vision maintenance techniques (Fig.8).The advan-tages of these new vision systems are improved handlingaccuracy and time savings in endoscopic manipulations[19±21].In recent years endoscopic surgery has become increas-ingly widespread,supported by new developments in theinstrumentation available.Less attention has been paid tothe comfort of the ®rst surgeon and his assistant,who wereoften forced into tiring standing positions and monotonoustasks.Moreover,high costs of the operating theater,even forstandard laparoscopic procedures,require the involvementof less experienced fellows,such as residents,which leads toa further increase in the operation time.Especially incommunity hospitals and private institutions,where therole of the surgical assistant is assumed either by assistantphysicians or trained nurses,the introduction of positioningsystems for laparoscopic procedures may alleviate some ofthe pressure due to limited resources.Improved architecturedesign and interface of systems will lead to improved ergon-omy and intuitive mode of operation of systems,in order tooffer the surgeons better control.Restoration of full instrument mobility is a further tech-nological challenge in endoscopic surgery.First prototypesof steerable endoscopic instruments with two additionalDOF were introduced by our group in 1992 [22].A ®rstfunctional master slave manipulator for surgery was intro-duced by Hill et al.,fromSRI International,Menlo Park,CA[15].The SRI telemanipulator was not designed for endo-scopic use and had only four DOF in its ®rst alignment ofthe grasper according to the operative situation.The restoration of full spatial mobility of the instrumentin laparoscopic or thoracoscopic surgery is a complexresearch task.The ARTEMIS system was the ®rst 6 DOFmaster-slave manipulator for endoscopic surgery found inthe literature [23].Clinical use of the system,however,willrequire further development in the area of slave mechanicsand the control system.Intensive research and developmentefforts are currently put on manipulators for endoscopicmicrosurgery by various work groups at scienti®c institu-tions and industry.Several devices have already enteredpreclinical testing,and it appears to be highly probablethat master slave manipulators will be in practical surgicaluse before the next millennium.References[1] Becker H,Melzer A,Schurr MO,Buess G.3D video techniques inendoscopic surgery.Endosc Surg Allied Technol 1993;1:36±39.[2] Crosthwaite G,Chung T,Dunkley P,Shimi S,Cuschieri A.Compar-ison of direct vision and electronic two- and three-dimensionaldisplay systems on surgical task ef®ciency in endoscopic surgery.Br J Surg 1995;82:846±851.[3] Schurr MO,Buess G,Kunert W,Flemming E,Hermeking H,GumbL.Human sense of vision:a guide to future endoscopic imagingsystems.Min Invas Ther Allied Technol 1996;5:410±441.[4] Begin E,Gagner M,Hurteau R,Santis S,Pomp A.A robotic camerafor laparoscopic surgery:conception and 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